This is a two-piece set, so it can be worn as a dress, or the top can be paired with a skirt or pants as an inner layer, which is also cute. I have never worn it outside. I am tall, and the knee length felt short on me (crying). The size is 9. It fits tightly, so it makes you look slim (*^^*) When I, who am 168 cm tall, wear it, the length is at my knees. I have only worn it once, as a try-on.